Question

Tech Mahindra (Aptitude)
01. If a boat is moving in upstream with velocity of 18 km/hr and goes downstream with a
velocity of 60 km/hr, then what is the speed of the stream?
(a) 21 km/hr
(b) 26 km/hr
(c) 34 km/hr
(d) none of these​

Answer 1

Step-by-step explanation:

This is a question based on the concept of relative velocity.

Assuming,

V = Speed Of Boat in still water.

X = Speed Of River.

When moving downstream, the speed of the boat is the sum of it’s speed in still water and the speed of the river.

So, V + X = 40 Km/h

When moving upstream the boat moves slower (as the river opposes it’s motion).Now it’s speed is equal to it's speed in still water minus the speed of the river.

So, V - X = 14 Km/h

Solving these equations we get, X = 13 Km/h.

Thus speed of the stream is 13 Km/hr.

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Answer 2

Step-by-step explanation:

when it is moving downstream=V+X=60

when it is moving upstream =V-X=18

where V= Velocity of boat

X=Velocity of stream

By solving above equations X=21